LINQ ToList() causes all records to be the last one off a coroutine -

i seem have misunderstanding because following code works correctly if don't append tolist() command:

ienumerable<processorinfo> query = (         n in infoget(emachineinfodepth.logicalprocessor)         select n     )     .tolist(); 

infoget looks this:

internal static ienumerable<processorinfo> infoget(emachineinfodepth depth) {     processorinfo result = new processorinfo();      // loop through workgroups     foreach (workgroup wg in workgroups_s)     {         result.workgroup = wg;          if (depth >= emachineinfodepth.numanode)         {             // loop through numanodes             foreach (numanode node in wg.numanodes)             {                 result.numanode = node;                  if (depth >= emachineinfodepth.cpu)                 {                     // loop through cpus                     foreach (cpu cpu in node.cpus)                     {                         result.cpu = cpu;                          if (depth >= emachineinfodepth.core)                         {                             // loop through cores                             foreach (core core in cpu.cores)                             {                                 result.core = core;                                  if (depth >= emachineinfodepth.logicalprocessor)                                 {                                     // loop through logicalprocessors                                     foreach (logicalprocessor lp in core.logicalprocessors)                                     {                                         result.logicalproc = lp;                                          yield return result;                                     }                                 }                                 else                                 {                                     yield return result;                                 }                             }                         }                         else                         {                             yield return result;                         }                     }                 }                 else                 {                     yield return result;                 }             }         }         else         {             yield return result;         }     } } 

with tolist() correct count, records equal final element in sequence. while variable scope error in complex coroutine, in iterations see final value, why code work without tolist()?

my question is: misunderstanding?

problem is, you're returning reference same variable time:

processorinfo result = new processorinfo(); 

that's place you're creating new processorinfo object. change it's properties values later, return still same object.

you should consider adding copy constructor processorinfo() class, , replace every yield return result; call yield return new processorinfo(result);. easiest way make work.

update

it look works e.g. when you've saved variable state somewhere during loop:

foreach(var item in query) {     itemslist.add(item);     propertylist.add(item.intproperty); } 

after call itemslist contain incorrect data, while propertylist fine.